/*
 *    BasicClassificationPerformanceEvaluator.java
 *    Copyright (C) 2007 University of Waikato, Hamilton, New Zealand
 *    @author Richard Kirkby (rkirkby@cs.waikato.ac.nz)
 *
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
package moa.evaluation;

import moa.AbstractMOAObject;
import moa.core.Measurement;
import weka.core.Utils;

public class BasicClassificationPerformanceEvaluator extends AbstractMOAObject
		implements ClassificationPerformanceEvaluator {

	private static final long serialVersionUID = 1L;

	protected double weightObserved;

	protected double weightCorrect;

	public void reset() {
		this.weightObserved = 0.0;
		this.weightCorrect = 0.0;
	}

	public void addClassificationAttempt(int trueClass, double[] classVotes,
			double weight) {
		if (weight > 0.0) {
			this.weightObserved += weight;
			if (Utils.maxIndex(classVotes) == trueClass) {
				this.weightCorrect += weight;
			}
		}
	}

	public Measurement[] getPerformanceMeasurements() {
		return new Measurement[] {
				new Measurement("classified instances",
						getTotalWeightObserved()),
				new Measurement("classifications correct (percent)",
						getFractionCorrectlyClassified() * 100.0) };
	}

	public double getTotalWeightObserved() {
		return this.weightObserved;
	}

	public double getFractionCorrectlyClassified() {
		return this.weightObserved > 0.0 ? this.weightCorrect
				/ this.weightObserved : 0.0;
	}

	public double getFractionIncorrectlyClassified() {
		return 1.0 - getFractionCorrectlyClassified();
	}

	public void getDescription(StringBuilder sb, int indent) {
		Measurement.getMeasurementsDescription(getPerformanceMeasurements(),
				sb, indent);
	}

}
